Field emission display (FED) devices are used to project images onto a surface. A typical FED includes an electron emission source, or cathode, and an anode, which is disposed in spaced-apart relation to the cathode. When a voltage potential of appropriate polarity is applied between the anode and cathode, electrons are emitted from the cathode and are accelerated toward the anode. The anode may be at least partially coated with a fluorescent material. Thus, when the electrons collide with the coated portions of the anode, light is emitted, providing a suitable image. Some FEDs may also include a gate electrode positioned between the cathode and anode. A voltage potential may also be applied to the gate electrode to enhance and/or control the electron flow from the cathode to the anode.
Recently, FEDs began being constructed using carbon nanotubes as the electron emission source, due in part to the low fabrication cost and placement possibilities associated with carbon nanotubes. For example, low cost processes, such as chemical vapor deposition (CVD) and a paste process, are being used to manufacture this type of FED. One drawback associated with these low cost processes is that these techniques can, in many instances, result in residual nanotubes in unwanted areas of the FED. Because carbon nanotubes exhibit relatively high conductivity and may be physically sharp, these residual nanotubes can cause electrical shorts, spurious gate leakage, and spurious anode leakage, all of which may cause image display defects.
Conventionally known cleaning methods are ineffective, and/or degrade FED device field emission properties, and/or are expensive and/or time consuming. For example, one known method used in the display business destroys metal trace lines leading to areas with electrical defects. When applied over a large area, this method is tedious, time-consuming, and involves iteration through electrical testing. Thus, a relatively large yield loss may be experienced by FED device manufacturers.
Hence, there is a need for a method of removing residual nanotubes from unwanted areas of FEDs that does not degrade FED device field emission properties, and/or is not expensive, and/or is not time-consuming. The present invention addresses one or more of these needs.